The objectives of this proposal are to establish the structural bases for the biological activities of heparins and heparan sulfates. The primary emphases will be placed on the application of newer methodology, developed in previous grant periods and in the proposal period, to establish the primary oligosaccharide sequences that occur in these polymers. Heparin and haparan sulfate will be converted to oligosaccharides by partial or complete cleavage of the polymer using (a) nitrous acid, which specifically cleaves the glycosidic bonds of N-sulfated glucosamine residues (at pH 1.5) or N-unsubstituted glucosamie residues (at pH 4), (b) periodate oxidation/borohydride reduction/mild acid hydrolysis (Smith degradation), which cleaves these polymers specifically at unsulfated uronic acid residues, or (c) N-deacetylation/deamination, which cleaves the glycosidic bonds of N-acetylated glucosamine residues. The oligosaccharides will be labeled by reduction with NaB3H4 and separated by high pressure liquid chromatography. The structures of chromatographically homogenous oligosaccharides will be determined by sequential depolymerization to their basic disaccharide units which can be identified by HPLC. Profiling procedures for defining structural differences in different heparin and heparan sulfate fractions will be developed and applied in the characterization of heparin having high anticoagulant activity.